about

writing

contact

Ensuring Proper New DST Compliance

By eric

2007-03-06

By now, if you haven’t heard about the change in daylight savings time (DST), then you need to break out from under your rock and update your servers. That’s where luckily, I come in. No, I won’t update your servers for you (unless you pay me and even then it’s iffy), but I will guide you along in updating them.

Before I jump headlong into helping you out, I feel as though (since it’s my blog anyway) that I just want to rant for a minute…

<rant>I heard that we tried this a while back and they had kids walking to school in the dark…which in and of itself isn’t good. So we figure, let’s try it again. If we can just save a little bit of money by everyone using 1 hour or so less power for 2 weeks, that everything would be dandy. I don’t think anyone took into account the man hours that it would take to update all the software and all the hardware and every little thing that uses dates and has relied on the system that we used for many years. And amusingly enough, if someone doesn’t get everything perfect with the updates for the power systems, then who knows, this may require people to use more power to make up for mistakes. Who’d have thought something like this has the possibility to backfire?</rant>

The first thing you need to do is to check to see if you are updated and ready to go. To do that, if you are in the EST/EDT timezone and your system isn’t updated, then it will look like this when you give it the following command:

It will say “Not New DST Compliant” if your setup isn’t currently in compliance with the new DST setup.

To become DST compliant, all you really have to do is update your versions libc6 and locales. This update will ensure that your timezone data is up to date and your system will then respond to the time change accordingly. On a Debian, Ubuntu, or other apt based system, you will only have to do the following (note the ‘#’ means we are already root, if you are on Ubuntu, put a sudo in front of the command):

1

# apt-get update && apt-get install libc6 locales

Gentoo:

1

# emerge --sync && emerge sys-libs/timezone-data

If all went well, then you should be able to execute the same command as above and it will look like this:

The Gentoo instructions did not work for me. I have two Gentoo machines. Both use ntp for setting the time. Machine ‘A’ shows the correct time, yet does not have sys-libs/timezone-data installed, and zdump shows it thinks DST doesn’t start until April (I’m in the PST zone). Machine ‘B’ does have sys-libs/timezone-data installed, yet zdump shows that it also thinks DST doesn’t start until April, and machine B’s clock is behind by one hour (i.e. it hasn’t applied DST yet).

The first thing I would say to do is to check your /etc/conf.d/clock file. Ensure that you have the proper timezone in there. I originally had America/New_York. That didn’t work so I changed it to EST5EDT and then reran ntpdate pool.ntp.org and it was sufficient. You may need to do something similar and make yours the equivilent (I’m not sure but I would assume its similar PST5PDT).